The present invention relates generally to valves and packing seals for valves. More particularly, the present invention relates to transverse seals for knife gate valves.
The objects of the present invention are attained by the provision of an improved transverse seal in a gate valve having an assembly portion and a gate. The assembly portion comprises a body, a chest and a top structure or bonnet. The improved transverse seal is located within the chest of the assembly portion and is in constant contact with the gate on each side of the gate. This transverse seal comprises a pliable, longitudinally extending casing of generally U-shaped cross section having a bottom member in contact with the gate and two oppositely disposed leg members. The bottom member is provided with a plurality of raised ribs. A packing material rests within the cavity of the casing, to provide support and pressure on the transverse seal. The oppositely disposed leg members also include longitudinally extending flanges at their distal ends. A rigid scraping blade is placed adjacent to each leg member and rests on its corresponding flange such that one edge of the scraping blade continuously contacts the gate. As these blades are placed at opposite sides of the casing, they produce a cleaning effect by wiping material from the gate. Furthermore, the positioning of the scraping blades adjacent to the leg member and its corresponding flange secures the transverse seal in its groove, and prevents "rolling" of the transverse seal into the gate receiving channel.
Other objects, advantages and novel features of the present invention will become apparent in the following detailed description of the invention when considered in conjunction with the accompanying drawing.